This invention relates to air-sampling apparatus. In particular, it concerns cartridges for carrying packings of adsorbent material and for collecting compounds such as N-nitrosamines from air for subsequent analysis.
The suspected presence in air of certain organic compounds which are harmful to animals, and may be harmful to people, makes it desirable to monitor the air in certain locations to identify specific compounds and determine their concentrations. One class of organic compounds of particular interest are N-nitrosamines or N-Nitroso compounds, which have the general formula ##STR1## where R.sub.1 and R.sub.2 are the same or different organic radicals. Several of these N-Nitroso compounds are known to be highly carcinogenic to animals and may be similarly harmful to people. Hence the recent discovery of certain airborne N-nitrosamines in factories and at other sites is cause for concern regarding exposure of workers to these compounds, and indicates that monitoring of such personnel and sites may be needed.
One known apparatus for collecting organic compounds such as N-nitrosamines from a sample of air is a trap which contains a liquid solution of potassium hydroxide through which an air sample is bubbled. Such "bubble traps", however, suffer from poor collection efficiency for certain compounds of interest, are too cumbersome for use as a personnel monitor, and yield a sample extract which is difficult and time-consuming to analyze.
Another collection device, described in U.S. Pat. No. 4,003,257 to Fletcher et al, comprises a glass test tube-like body open at one end and tapering to a small opening at the other end. The body is packed with an adsorbent material sold under the trademark TENAX-GC, which is held in place by glass wool at each end of the packing. These glass tubes are resistant to the moderately high temperatures used in subsequent desorption of the trapped volatile organic compounds, but may break during handling. The glass tubes also require a separate container for storage or transport, and lack features permitting their attachment to and use by a person in monitoring his breathing atmosphere.
Accordingly, it is an object of the invention to provide apparatus for carrying an adsorbent material, and particularly apparatus which in combination with the adsorbent material carried therein, is an improved air-sampling device.
It is an object of the invention to provide an air-sampling cartridge which may be readily attached to the clothing of a person and used to monitor air to which the person is exposed.
It is also an object of the invention to provide a disposable air-sampling cartridge which is easy to make and load with adsorbent material, and is convenient and safe to use in the collection of organic compounds.
It is a particular object of the invention to provide an air-sampling cartridge which facilitates accurate collection and analysis of air samples containing N-Nitroso compounds.